Topic: Wii Nunchuck Control of Two Servos (making it as compact as possible) (Read 2681 times)previous topic - next topic

I apologize in advance but I'm a complete newbie at all of this. I have no programing experience, and I have never done anything like this before. I have more mechanical experience, but no skills with using programing code and computer hardware.

With that said, I am trying to make a small portable two servo motor device controlled with Wii Nunchuck joy stick. Looking to make the computer/motherboard as small and compact as possible (small enough to fit into an altos size tin, or even smaller!). And its going to be battery operated.

I'm trying to create a puppet with a tentacle-like snake neck that can be controlled with a Wii Nunchuck. I've got the mechanics down on the neck and will be using two servo motors to move it. So I've been reading up on pan-tilt mechanics with a Wii Nunchuck, but so far all the DIYs I've come across use way to big of a board, and are still a bit confusing to me. I really would like to use the Arduino Nano (http://arduino.cc/en/Main/ArduinoBoardNano) but I am unsure if this would work for my application or what parts to buy to make it work. I'm also mainly interested in just using the stick control feature on the Wii Nunchuck, and not the tilt.

What parts do I need to get? Do I have to get a breadboard? What components do I need to set it up for battery power based on this layout? What would be the best code to use for this set up?

Price isn't too much of a factor, looking to make it as compact as possible. Not interested in making the controls wireless at the moment (want to tackle the main components first). Open to suggestions on a good small/nano size servo motor that isn't too noisy. The neck itself is going to be about 3ft long, and will probably weigh about a pound.

Ok, this is rather simple if your only using the nunchuck and not the nunchuck + remote. The nunchuck communicates to the remote via I2C, or to SDA & SDC on the arduino. If you want to reuse the nunchuck, there is an adapter that you can buy on ebay (very cheap), or you can simply cut the cable and use your own wires. (If you plan on cutting the cable, make sure your wiring is correct before soldering)

So far the smallest arduinos are the micro, the nano, and the mini/pro, all of which should work. You just need to wire it up correctly and find a way to power both the arduino and the servos. The arduinos have a suggested range of voltages to supply to them, so check out the spec sheet, and the servos usually will need 6V, so you will need to use either an AC adapter or batteries. Now being that you are going to put it inside a metal container, I suggest you tape up the bottom so that nothing shorts out.

As HM indicated, the Nunchuck is easy to interface to the Arduino via I2C. However, it onlyoperates at 3.3V and the Nano is a 5V board, so you have to be careful. Check how much currentthe Nuncheck requires, as the Nano derives its 3.3V power from the USB chip, and that canonly provide 50mA or so.

You cannot power the servos straight from the arduino, it will damage the arduino. What you could do is get 5 volt regulator, and a diode. If you put a diode from the GND pin on the regulator and then to GND, it will increase the output to about 5.3V.

Now a regular 9V will last for about a half hour, due to a lack of sufficient current. Try a 9.6V or 7.2V battery pack.

As HM mentioned, you have some homework to do in regards powering all those devices. Especially, as I said, nunchuck is 3.3V only. Don't blowIt up. OTOH, the windweadow code for nun chuck works right the firsttime.

Awww, actually I got my info from the windmeadow page,http://www.windmeadow.com/node/42

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Attach white to the Arduino's ground, red to 5 volt+, green to analog pin 4, yellow to analog pin 5. The nunchuck is only supposed to get 3.3+ volts. So far it has worked fine at 5 volts, but be warned. I am guessing that using the higher voltage will shorten the nunchucks lifespan...........Consulting the chip's data sheet (ST LIS3L02AL), it looks like this could be caused by running it at 5V instead of 3.3V. It doesn't seem to do any harm, but you might get different readings at different supply voltages.

Also, note some of the comments in the Sparkfun page, so who knows? SF used to sell shieldsthat put 5V on SD cards too, so (I'm not sure they're experts either) https://www.sparkfun.com/products/9281